Ocean level

This document outlines the stages of life in a stream impacted by pollution. It shows zones of a stream from clean to septic and back to recovery, with different animal life at each stage based on oxygen and decomposition levels. The clean zone contains trout and mayflies with 8 ppm oxygen. The septic zone is devoid of fish but contains bacteria and worms due to anaerobic conditions and low oxygen. The recovery zone returns to trash fish as oxygen levels begin to increase again downstream.